The analysis and quantification of blood components is an important diagnostic tool for better understanding the physical condition of a patient. Since adequate noninvasive blood analysis technology is not currently available, blood samples still need to be obtained by invasive methods from a great number of patients every day and analyzed. A well known example of such needs is self-monitoring of glucose levels by a diabetic individual, e.g., performed at home. Upon doctors' recommendations and using such products, patients typically measure blood glucose level several (3-5) times a day as a way to monitor their success in controlling blood sugar levels. For many diabetics, the failure to test blood glucose regularly may result in damage to tissues and organs, such as kidney failure, blindness, hypertension, and other serious complications. Nevertheless, many diabetics do not measure their blood glucose regularly.
One important reason why patients fail to regularly take blood samples to self-monitor physiological conditions is that the existing monitoring techniques and products for sampling blood cause appreciable pain and discomfort during the sampling process. The current technique of self-administered blood sampling involves using lancets made of stainless steel cylindrical rods the tips of which are shaped to ease penetration into the tissue past the epidermis, into the dermis to rupture the blood vessels in the dermis. Typically, the lancet is propelled by a spring-loaded mechanism that pushes the sharp tip of the lancet into the skin. Studies on pain associated with blood sampling using lancets that are currently commercially available indicate that these lancets often cause considerable pain and large tissue damage. Attempts have been made to reduce pain by reducing the size of the lancet. However, this has not been shown to reduce the amount of pain to an acceptable level for many people.
Therefore, it is desirable to devise techniques of blood extraction and measurement that are easy to administer. There is a need for improved devices and methods for sampling blood that can be used with very little pain and discomfort to the patient.